Anatomy of Head and Neck Infections

ANATOMY OF
HEAD AND NECK INFECTIONS
Angelia Natili, MD
Faculty Advisor: Susan McCammon, MD
Grand Rounds Presentation
Department of Otolaryngology
The University of Texas Medical Branch (UTMB Health)
November 30, 2011
Images used without permission
INTRODUCTION
Infections are one of the most commonly
occurring head and neck pathologies
 Spread of infection can be predicted by anatomic
boundaries
 Mortality from head and neck infections has
decreased significantly since the advent of
antibiotics, but resistant organisms are
spreading into the community
 Diagnosis and treatment will not be focus of this
discussion

SPACES IN THE HEAD AND NECK
Sinuses
 Orbits
 Peritonsillar
 Parapharyngeal
 Submandibular
 Retropharyngeal
 Danger Space
 Prevertebral
 Masticator
 Ear

SINUSES
NASAL BORDERS
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Medially - the nasal septum (perpendicular plate of the
ethmoid bone, the vomer bone, and the septal cartilage)
Laterally - the nasal conchae; superior and middle
(ethmoid bone derivation), inferior (a bone itself), and
contributions from the lacrimal bone, the perpendicular
plate of the palatine bone, and the maxillary bone
Inferiorly - the horizontal plate of the maxillary bone
(anterior two thirds of the hard palate) and the horizontal
plate of the palatine bone (posterior third of the hard
palate)
Superiorly - the cribiform plate of the ethmoid bone (where
the nerve endings of the Olfactory Nerve (CN1) open to the
environment)
Posterior - none, the nasal cavity opens to the nasopharynx
via the choanae
SINUS ANATOMY
SINUS DRAINAGE PATTERNS
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Maxillary Sinus - The largest sinus, is found lateral and
inferior to the lateral nasal wall below the orbit. This sinus
drains, superiorly, to the middle meatus just below the
ethmoidal bulla.
Sphenoidal Sinus - This sinus is located in the posterior wall
of the nasal cavity and opens to the sphenoethmoidal recess
which is superior to the superior concha. Superior to this sinus
is the pituitary gland (hypophysis) in the sella turcica of the
sphenoid bone.
Frontal Sinus - The frontal sinuses are located in the frontal
bone of the cranium and extend across the forehead. These
sinuses drain down to the middle meatus via the frontonasal
duct into the anterior portion of the semilunar hiatus.
Ethmoidal Sinus - These sinuses resemble bubbles and are
located behind the superior lateral nasal wall. They are
divided into anterior, middle and posterior cells on the basis of
their drainage. The anterior cells drain to the middle meatus
in the posterior portion of the semilunar hiatus. The middle
sinuses empty to the center of the ethmoidal bulla. The
posterior sinuses empty to the superior meatus.
SINUS DRAINAGE
PATTERNS
SINUSITIS
A complex disease
process resulting
in blockage of
sinus drainage
and accumulation
of fluid leading to
bacterial
overgrowth. May
be treated
medically or
surgically, with
the goal of surgery
to alleviate
anatomic
obstructions.
ORBITS: CHANDLER CLASSIFICATION

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1. Periorbital (Preseptal) Cellulitis: eyelid edema,
erythema, tenderness; no vision changes, chemosis, proptosis,
or restriction of ocular muscles
2. Orbital Cellulitis: proptosis, chemosis, may cause vision
changes (anterior pupillary defect), may limit extraocular
muscles
3. Subperiosteal Abscess: collection of pus between bone
and periosteum, chemosis, may have proptosis, restrict
extraocular motion, and affect vision, requires urgent surgical
decompression
4. Orbital Abscess: collection of pus in orbital soft tissue,
proptosis, chemosis, restricted extraocular motion, may have
no light perception (may be reversible), requires urgent
surgical decompression
5. Cavernous Sinus Thrombosis: Pathophysiology:
perinasal sinus infection ➝ orbital extension ➝ mural
thrombus forms in vessel wall (thrombophlebitis)
➝ propagates distally as clot softens and begins to seed


Pathogens: S. aureus, hemolytic Streptococcus and Pneumococcus
SSx: “picket fence” spiking fevers, toxemia, papilledema, paralysis of
extraocular muscles (CN III, IV, and V), proptosis, chemosis, eyelid
edema
ORBITAL
CELLULITIS
A WORD ABOUT THE CAVERNOUS SINUS
NOTES:The cavernous sinuses are paired, venous structures located on either side of the
sella turcica. They receive venous tributaries from the superior and inferior orbital veins
and drain into the superior and inferior petrosal sinuses. The cavernous sinus contains
the carotid artery, its sympathetic plexus, and the oculomotor nerves (third, fourth, and
sixth cranial nerves). In addition, the ophthalmic branch and occasionally the maxillary
branch of the fifth nerve traverse the cavernous sinus. The nerves pass through the wall
of the sinus while the carotid artery passes through the sinus itself.
PERITONSILLAR SPACE

The peritonsillar space consists of
loose connective tissue between the
capsule of the palatine tonsil and the
superior constrictor muscle. The
anterior and posterior tonsillar pillars
contribute to its anterior and
posterior borders, respectively. The
posterior tongue forms the inferior
boundary. Peritonsillar infections
may readily spread to the
parapharyngeal space.
DEEP SPACES
Submandibular
space
NOTES: Supra hyoid section flattened. Note the parotid, submandibular and
sublingual glands, the mylohyoid , carotid sheath.
PARAPHARYNGEAL SPACE
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Other names: lateral pharyngeal or pharyngomaxillary space
Shape: inverted pyramid
Boundaries:
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Compartments:
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Superior: skull base
Inferior: junction of the posterior belly of the digastric muscle and greater cornu of the
hyoid bone
Anterior: pterygomandibular raphe and medial pterygoid muscle bound the space
Posterior: prevertebral fascia
Medial: superior constrictor, tensor, and levator veli palatini muscles
Lateral: parotid gland, mandible, and lateral pterygoid muscle
Prestyloid (anterior): contains fat, styloglossus and stylopharyngeus, lymph nodes,
deep lobe of the parotid, internal maxillary artery, inferior alveolar, lingual, and
auriculotemporal nerves
Poststyloid (posterior): contains carotid artery, internal jugular vein, sympathetic
chain, and cranial nerves IX, X, XI, and XII.
Connections to other deep spaces:

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posteromedially: retropharyngeal space
inferiorly: submandibular space
laterally: masticator space
medially: peritonsillar space
PARAPHARYNGEAL SPACE
PARAPHARYNGEAL SPACE
SUBMANDIBULAR SPACE

Boundaries:
Superior: mucosa of the floor of the mouth
Inferior: digastrics muscle and hyoid bone
Anterior: mylohyoid muscle and anterior belly of digastrics
Posterior: posterior belly of the digastric and stylomandibular
ligament
 Medial: hyoglossus, mylohyoid, styloglossus, genioglossus, and
geniohyoid muscles
 Lateral: platysma and mandible
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The mylohyoid muscle divides the submandibular space into
a superior sublingual space and an inferior submaxillary
space (also referred to as the submandibular space).

Sublingual space: lateral to the geniohyoid and genioglossus muscles,
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Contains: sublingual gland and Wharton’s duct.
Teeth apices anterior to the second molar lie superior to the mylohyoid line
and thus involve the sublingual space.
Submaxillary space


Contains submandibular glands and lymph nodes.
Infections of the second and third molars initially involve the submandibular
or parapharyngeal space, because their roots extend below the mylohyoid
line.
LUDWIG’S ANGINA
Sublingual space
Submaxillary space
RETROPHARYNGEAL SPACE
Potential space
 Boundaries:

Upper: skull base
 Lower: mediastinum at the tracheal bifurcation
 Anterior: buccopharyngeal fascia, lining of the
posterior pharynx and esophagus
 Posterior: alar fascia

Contains: lymph node and connective tissue
 Routes of entry: direct spread from the
parapharyngeal space, or lymphatic spread from
the paranasal sinuses or nasopharyngeal region

Submandibular
space
Danger,
Will
Robinson!
DANGER SPACE
Potential Space, dangerous for rapid inferior
spread of infection to the posterior mediastinum
through its loose areolar tissue
 Boundaries

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Superior: skull base
Inferior: diaphragm
Anterior: alar fascia, retropharyngeal space
Posterior: prevertebral fascia
Lateral: transverse processes of vertebrae
Contains: sympathetic trunk
 Routes of entry: retropharyngeal,
parapharyngeal, or prevertebral spaces

DANGER SPACE
PREVERTEBRALSPACE
Potential space
 Boundaries

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Superior: clivus of the skull base
Inferior: coccyx
Anterior: prevertebral fascia
Posterior: vertebral bodies
Lateral: transverse processes
Contains: paraspinous, prevertebral, and scalene
muscles, vertebral artery and vein, brachial
plexus, and phrenic nerve
 Routes of entry: infection of the vertebral bodies
and penetrating injuries

PREVERTEBRAL SPACE
MASTICATOR SPACE
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Boundaries:
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Superior: skull base
Inferior: submandibular space
Lateral: masseter, superficial temporal fascia
Medial: medial pterygoid, parapharyngeal space
Anterior: posterior wall of maxillary sinus, buccal space
Posterior: parotid
Contains: mandible and muscles of mastication (masseter, temporalis,
medial pterygoid, lateral pterygoid), the third portion of the
trigeminal nerve, which enters through the foramen ovale, the
internal maxillary artery, and much of the buccal fat pad
Subspaces:
Masseteric: between the masseter muscle and ramus of mandible
Pterygoid: between the pterygoid muscles and ramus
Superficial temporal: superficial temporal fascia and temporalis muscle
 Deep temporal: between the deep temporal fascia and temporal bone
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Route of entry: most commonly from the third mandibular molars
MASTICATOR SPACE
Graphic representation (axial view) of
structures of the left masticator space:
(1) masseter muscle; (2) medial pterygoid
muscle; (3) lateral pterygoid muscle; (4)
temporalis muscle; (5) pterygopalatine
fossa; and (6) sphenopalatine foramen.
MASTICATOR SPACE WITH SUBSPACES
EAR
Necrotizing otitis externa is an aggressive and
potentially fatal infection originating in the
external canal, with progressive spread along the
soft tissues and bone of the skull base, ultimately
involving intracranial structures.
 Posterior spread (usually of P. aeruginosa) leads
to clouding of the mastoid air cells. With medial
spread, displacement and erosion of ossicles
occur, while anterior spread may produce
temporomandibular joint arthritis and
mandibular condyle osteomyelitis. Intracranial
spread may result in meningitis, brain abscess or
cavernous sinus thrombosis.

NECROTIZING OTITIS EXTERNA
Showing invasion into
parapharyngeal space
CONCLUSION


Understanding anatomical boundaries can help
clinicians manage head and neck infections by
predicting their spread
Mortality has decreased significantly in the
postantibiotic era
REFERENCES
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http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/allergy
/rhino-sinusitis/
http://doctorcayoo.blogspot.com/2009/12/peritonsiler-abscess-pta-quinsy-1.html
www.merckmanuals.com/professional/eye_disorde...
http://iris3.med.tufts.edu/dentgross/labguide/Homepage.html
Cummings Otolaryngology Head and Neck Surgery, 5th ed.
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Family Physician, September 1991, Vol 44, no 3, 878-888
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